What is the word used for "kill"?
So I thought that was an interesting suggestion. So I looked up the word, and it was "phoneio" or something like that. But then I found a footnote in a website that republished the homily and it talked about that part. "Nesteia" literally means not to eat. So the idea of fasting is to starve sin to death (literally killing sin) from the foods it feeds on to propagate itself, almost like a parasite in your body.
So "fasting" or "starving" kills, and it particularly kills sin.
Thank you for the suggestion. That answers it for me